1. Field of the Invention
The present invention relates generally to a program, method and apparatus for virtual storage management that assign physical volumes managed in a pool to virtual volumes having a capacity designated by a user, and more particularly, to a program, method and apparatus for virtual storage management that select logic volumes such that the logic volumes satisfies reliability, serviceability and performance to assign the selected logic volumes to virtual volumes.
2. Description of the Related Art
Conventionally, a virtual storage system has been known, that collectively manages a plurality of disk storages by making those storages virtual, and assigns virtual volumes to a server. In such a virtual storage system, the disk storages that have been made virtual are arranged between a server and physical disks and the server accesses the virtual disks managed as being virtual. Thereby, operation and management of the physical storages can be completely separated from the server and an open storage area network (SAN) environment that does not rely on any hardware can be constructed. A virtual storage system is realized by a control apparatus that is arranged between a server and physical storages and executes a virtual storage management program. This control apparatus constructs for the server a virtual storage environment consisting of a storage pool that registers the physical disks and switches that are made virtual, and assigns a physical disk having a capacity that a user desires corresponding to an application of the server, to a virtual disk from the storage pool. As the conventional assignment of physical disks constituting virtual disks, physical disks are assigned after executing appropriate sizing to a capacity designated by a user in designing of the system configuration. A system is known that divides apparatuses into groups by type and assigns physical apparatuses to virtual disks for each group in the case where a plurality of types of apparatuses such as a magnetic disk apparatus, an optical disk apparatus and a semiconductor memory apparatus are present being mixed as logic volumes. However, as the assignment of the physical apparatuses to the virtual apparatuses, the physical apparatuses are assigned after executing appropriate sizing in designing of the system configuration, similarly to the above.
However, in such a method of assigning physical disks to virtual disks after executing appropriate sizing in a conventional system configuration design, whether or not the physical disks are disks that have not yet been assigned is determined when the physical disks are assigned to the virtual disks, and physical disks that are not yet assigned are selected and assigned. Therefore, each capacity designated by a user is limited to a whole number times as large as the capacity of a physical disk and, thus, the capacity designated by the user tends to be larger than a necessary capacity. Therefore, wasteful assigned volumes are generated by the capacity over-assigned. In order to assign physical disks corresponding to a capacity designated by a user, it is necessary to assign a portion of areas of physical disks that are not yet assigned. Therefore, the disks that are the target of the assignment include disks that are not yet assigned and the disks that are partially not assigned, being mixed. As a result, assignment to the virtual disks taking into account not only the disks that are not yet assigned but also the disks that are partially not yet assigned is necessary. However, it is still remains as a task, that what type of assignment method should be constructed for the disks that are partially not assigned. Furthermore, it is also remains as a significant task, that how the physical disks that can constitute the virtual disks that are optimal for a user application should be assigned based on the specifications such as the configuration and performance of RAID apparatuses constituting the physical disks and a controller of those RAID apparatuses.